Physics fixes, control fixes, credits

Fixed problem with incorrect charge/mass ratio…turned out that my value
for µ0 was accidentally ten times too high (had it as 4*PI*10e-7,
instead of PI*4e-7).

Made all controls scale to programmer-adjustable maximum/minimum SI
values.

Added credit to inspire contact.

DO NOT ATTEMPT TO RESIZE WINDOW - mega-crashed my computer.